Because Magic: The Gathering doesn’t have enough different formats yet, Wizards of the Coast has seen fit to give official recognition — whatever that means — to a fan-created format called “Oathbreaker.” You can find the official announcement here, and the official website for rules and banned list updates is oathbreakermtg.org.
My initial reaction to learning of the format was one of quick dismissal. I tried the Tiny Leaders format with friends many years ago, and this experiment ended up quickly devolving into a very uninteresting experience. I don’t think that format has any real legs, at best serving a small niche of players who like degenerate games of Magic with only the impression of variance.
Oathbreaker has some of the same issues as Tiny Leaders, but not the same. Even my favourite constructed format, Commander, has the problem where guaranteed access to card(s) can be frustrating and game-warping. It can be very difficult to deal with a player who can simply keep re-casting one of their key cards every turn or so, regardless of how many times you deal with it. Oathbreaker replaces the ‘commander,’ a unique legendary creature, with a planeswalker, while also giving you a spell that can be accessed in the same way.
My cursory view of the format appears to be a morass of overly competitive decks, given the format allows stuff like Oko, Thief of Crowns — one of the most maligned and banned cards in the game — as the planeswalker of choice, and there are a plethora of combo decks to choose from. I understand that different players have entirely different sensibilities when it comes to what constitutes fun and fair gameplay, but Oathbreaker does not seem to have mass appeal in mind — this looks like something for competitive Commander (cEDH) players to do when they’re bored.
Ultimately, I don’t think this official recognition will lead anywhere, especially when the format is unavailable on any of the official digital platforms. At best, this will end up like Brawl — another attempt to cash in on Commander that will ultimately be discarded by most players and Wizards of the Coast themselves.